(1) Field of the Invention
The present invention relates generally to circular knitted fabric and, more particularly, to a two end fleece fabric having a weight of between about 8 to 12 oz. per sq.yd.
(2) Description of the Prior Art
The term circular knitting covers those weft knitting machines having needle beds arranged in circular cylinders and/or dials including latch, bearded and occasionally compound needle machinery. Such machines produce a wide variety of fabric structures, garments, hosiery and other articles and a variety of diameters and machine gauges. Such machines have the needles fixed in a revolving circle with the loop formation and knitting action being achieved by ancillary elements moving yarn and loops along the needle stems producing a fabric tube with the technical face facing backwards.
Large diameter circular knitting machines are generally used to produce either fleece or jersey fabrics as well as other fabric constructions. Because of the seasonal nature of these fabrics, it is usually necessary to maintain both fleece and jersey machines on the knitting floor or to move machines in and out as seasonal fabric demands change. Both approaches are capital and labor cost intensive.
One approach to solving this problem is disclosed in U.S. Pat. No. 5,613,375, issued to Renda et al., the entire disclosure hereby being incorporated by reference. This patent teaches a new and improved circular knitting machine having interchangeable section blocks and sinkers which allow the machine to be converted between producing two end fleece and 4 track jersey fabrics by simply replacing the section blocks, carrier ring, needles and sinkers without the need to strip the machine to its bed or to change the feeders or creel.
The following discussion is taken generally from Spencer, David J., Knitting Technology, (2d. ed. 1989), which is a general treatment of knitting technology.
Knitted fabrics are progressively built up by converting newly fed yarn into new loops in the needle hooks, the needles then draw these new loops head first through the old loops, which have been retained from the previous knitting cycle. The needles at the same time release, cast off or knock-over old loops so that they hang suspended by their heads from the feet of the new loops whose heads are still held in the hooks of the needles. A cohesive structure is thus produced by a combination of the intermeshed loops and the yarn joining those loops together through which it passes.
Knitted loops are arranged in rows and columns roughly equivalent to the warp and weft of woven structures termed "courses" and "wales" respectively. A course is a predominately horizontal row of loops (in an upright fabric) produced by adjacent needles during the same knitting cycle. A wale is a predominantly vertical column of needle loops produced by the same needle knitting at successive knitting cycles and thus intermeshing each new loop through the previous loop.
The term "stitch density" is frequently used in knitting instead of a linear measurement of courses and wales, it is the total number of needle loops in a square area measurement such as square inch. It is obtained by multiplying the number of courses per inch by the number of wales per inch. Stitch density tends to be a more accurate measurement because tension acting in one direction in the fabric may, for example, produce a low reading for the courses and a high reading for the wales, which when multiplied together cancel the effect out.
"Yarn count" indicates the linear density (yarn diameter or fineness) to which that particular yarn has been spun. The choice of yarn count is restricted by the type of knitting machine employed and the knitting construction. The yarn count, in turn, influences the cost, weight, opacity, handle and drapability of the resulting knitted structure. In general, staple spun yarns tend to be comparatively more expensive the finer their count, because finer fibers and a more exacting spinning process are necessary in order to prevent the yarn from showing an irregular appearance.
Historically, most systems are associated with particular yarn-spinning systems, for example, a yarn spun on the worsted system from acrylic fibers may be given a worsted count number. The worsted system is of the indirect type based on length per fixed unit mass, i.e., the higher the count number, the finer the yarn. The weight is fixed (1 lb.) and the length unit (number of 560-yard hanks) varies. 1/24's worsted (24.times.560-hank yards weighing 1 lb.) will be twice the cross-sectional area of 1/48's worsted (48.times.560-yard hanks weighing 1 lb.). 2/24's worsted indicates that the yarn contains two ends of 1/24's so that the resulting count is twice the cross-sectional area (24/2=12's).
Three end and two end, course cut (10 to 14), knitting techniques are conventionally used to produce knitted fleece with low stitch densities (600-700). Fabric with a higher stitch density is generally perceived to be a higher quality fabric because it has a lower shrinkage rate and a more stable print platform.
Two end, course cut knitting techniques are generally used to produce knitted fleece fabric with lower stitch density, which is generally perceived to be low quality fabric. Two end knitted fleece fabric constructions are typically less costly to produce compared to three end knitted fleece fabric constructions because of lower yarn material costs.
Both three end and two end course cut knitting techniques can be used to produce knitted fleece fabric having the same fabric weight and the same stitch density. However, because three end knitting uses three yarn ends, as opposed to two yarn ends used by two end knitting, a yarn having a finer yarn count, which is significantly more expensive, is necessary to produce knitted fleece fabric with the same fabric weight and same stitch density. Thus, it is much more costly to produce knitted fleece fabric of a given weight and stitch density using a three end knitting technique.
Thus, there remains a need for a new and improved knitted fleece fabric that can be produced economically, and which has a relatively high stitch density and correspondingly low shrinkage rate, and that has an extremely stable print platform. This has been found possible to achieve using a two end, fine cut (greater than about 14) knitting technique using more economical yarns than possible with three ends and a significantly higher stitch density.